TY - JOUR AB - The photoionization properties of the pharmaceutically relevant substances amantadine, diazepam, dimethyltryptamine, etomidate, ketamine, mescaline, methadone, and propofol were determined. At beamline U125/2-10m-NIM of the BESSY II synchrotron facility (Berlin, Germany) vacuum ultraviolet (VUV) photoionization spectra were recorded in the energy range 7.1 to 11.9 eV (174.6 to 104.2 nm), showing the hitherto unknown ionization energies and fragmentation appearance energies of the compounds under investigation. Furthermore, (1+1)-resonance-enhanced multiphoton ionization (REMPI) spectra of selected compounds (amantadine, diazepam, etomidate, ketamine, and propofol) were recorded by a continuous scan in the energy range between 3.6 and 5.7 eV (345 to 218 mu) using a tunable optical parametric oscillator (spectral resolution: 0.1 mu) laser system. The resulting REMPI wavelength spectra of these compounds are discussed and put into context with already known UV absorption data. Time-of-flight mass spectrometry was used for ion detection in both experiments. Finally, the implications of the obtained physical-chemical results for potential analytical applications are discussed. In this context, fast detection approaches for the considered compounds from breath gas using photoionization mass spectrometry and a rapid pre-concentration step (e.g., needle trap device) are of interest. AU - Kleeblatt, J. AU - Ehlert, S. AU - Hölzer, J. AU - Sklorz, M. AU - Rittgen, J. AU - Baumgartel, P.* AU - Schubert, J.K.* AU - Zimmermann, R. C1 - 26922 C2 - 32494 SP - 860-872 TI - Investigation of the photoionization properties of pharmaceutically relevant substances by resonance-enhanced multiphoton ionization spectroscopy and single-photon ionization spectroscopy using synchrotron radiation. JO - Appl. Spectrosc. VL - 67 IS - 8 PB - Soc. Applied Spectroscopy PY - 2013 SN - 0003-7028 ER - TY - JOUR AB - This work describes a fast and reliable method for determination of photoionization cross-sections (PICS) by means of gas chromatography (GC) coupled to single-photon ionization mass spectrometry (SPI-MS). Photoionization efficiency (PIE) data for 69 substances was obtained at a photon energy of 9.8 ± 0.4 eV using an innovative electron-beam-pumped rare gas excimer light source (EBEL) filled with argon. The investigated analytes comprise 12 alkylbenzenes as well as 11 other substituted benzenes, 23 n-alkanes, ten polyaromatic hydrocarbons, seven aromatic heterocycles, and six polyaromatic heterocycles. Absolute PICS for each substance at 9.8 eV are calculated from the relative photoionization efficiencies of the compounds with respect to benzene, whose photoionization cross-section data is well known. Furthermore, a direct correlation between the type of benzene substituents and their absolute PICS is presented and discussed in depth. Finally, comparison of previously measured photoionization cross-sections for 20 substances shows good agreement with the data of the present work. AU - Eschner, M.S. AU - Zimmermann, R. C1 - 6894 C2 - 29418 SP - 806-816 TI - Determination of photoionization cross-sections of different organic molecules using gas chromatography coupled to single-photon ionization (SPI) time-of-flight mass spectrometry (TOF-MS) with an electron-beam-pumped rare gas excimer light source (EBEL): Influence of molecular structure and analytical implications. JO - Appl. Spectrosc. VL - 65 IS - 7 PB - Soc Applied Spectroscopy PY - 2011 SN - 0003-7028 ER - TY - JOUR AB - Several ionization potentials (IPs) of security relevant substances were determined with single photon ionization time of flight mass spectrometry (SPI-TOFMS) using monochromatized synchrotron radiation from the "Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung" (BESSY). In detail, the IPs of nine explosives and related compounds, seven narcotics and narcotics precursors, and one chemical warfare agent (CWA) precursor were determined, whereas six IPs already known from the literature were verified correctly. From seven other substances, including one CWA precursor, the IP could not be determined as the molecule ion peak could not be detected. For these substances the appearance energy (AE) of a main fragment was determined. The analyzed security-relevant substances showed IPs significantly below the IPs of common matrix compounds such as nitrogen and oxygen. Therefore, it is possible to find photon energies in between, whereby the molecules of interest can be detected with SPI in very low concentrations due to the shielding of the matrix. All determined IPs except the one of the explosive EGDN were below 10.5 eV. Hence, laser-generated 118 nm photons can be applied for detecting almost all security-relevant substances by, e.g., SPI-TOFMS. AU - Schramm, E. AU - Mühlberger, F. AU - Mitschke, S. AU - Reichardt, G. AU - Schulte-Ladbeck, R.* AU - Pütz, M.* AU - Zimmermann, R. C1 - 1572 C2 - 25313 SP - 238-247 TI - Determination of the ionization potentials of security-relevant substances with single photon ionization mass spectrometry using synchrotron radiation. JO - Appl. Spectrosc. VL - 62 IS - 2 PY - 2008 SN - 0003-7028 ER - TY - JOUR AB - Resonance-enhanced multiphoton ionization (REMPI) combined with time-of-flight mass spectrometry (TOFMS) is an analytical method capable of on-line monitoring of trace compounds in complex matrices. A necessary prerequisite for substance selective detection is spectroscopic investigation of the target molecules. Several organic nitrogen compounds comprising aliphatic and aromatic amines, nitrogen heterocyclic compounds, and aromatic nitriles are spectroscopically investigated with a tunable narrow bandwidth optical parametric oscillator (OPO) laser system providing a scannable wavelength range between 220 and 340 nm. These species are known as possible precursors in fuel-NO formation from combustion of solid fuels such as biomass and waste. A newly conceived double inlet system was used in this study, which allows rapid change between effusive and supersonic molecular beams. The resulting REMPI spectra of the compounds are discussed with respect to electronic transitions that could be utilized for a selective ionization of these compounds in complex mixtures such as combustion and process gases. The practicability of this approach is demonstrated by wavelength selected on-line REMPI-TOFMS detection of aniline and cyanonaphthalene in the burning chamber of a waste incineration plant. REMPI mass spectra recorded at different excitation wavelengths as well as variations in time show the utilization of species-selective REMPI-TOFMS detection for on-line monitoring of crucial substances in pollutant formation. AU - Streibel, T. AU - Hafner, K. AU - Mühlberger, F. AU - Adam, T. AU - Zimmermann, R. C1 - 2138 C2 - 23515 SP - 72-79 TI - Resonance-enhanced multiphoton ionization time-of-flight mass spectrometry for detection of nitrogen containing aliphatic and aromatic compounds: Resonance-enhanced multiphoton ionization spectroscopic investigation and on-line analytical application. JO - Appl. Spectrosc. VL - 60 IS - 1 PY - 2006 SN - 0003-7028 ER - TY - JOUR AU - Uchimura, T.* AU - Hafner, K. AU - Zimmermann, K. AU - Imasaka, T.* C1 - 10348 C2 - 21095 SP - 461-465 TI - Multiphoton Ionization Mass Spectrometry of Chlorophenols as Indicators for Dioxins. JO - Appl. Spectrosc. VL - 57 PY - 2003 SN - 0003-7028 ER -